docs: def heightmap_add_voronoi(
      hm: np.ndarray,
      nbPoints: Any,
      nbCoef: int,
      coef: Sequence[float],
      rnd: Optional[tcod.random.Random] = None,
  ) -> None:
      """Add values from a Voronoi diagram to the heightmap.
  
      Args:
          hm (numpy.ndarray): A numpy.ndarray formatted for heightmap functions.
          nbPoints (Any): Number of Voronoi sites.
          nbCoef (int): The diagram value is calculated from the nbCoef
                        closest sites.
          coef (Sequence[float]): The distance to each site is scaled by the
                                  corresponding coef.
                                  Closest site : coef[0],
                                  second closest site : coef[1], ...
          rnd (Optional[Random]): A Random instance, or None.
      """
      nbPoints = len(coef)
      ccoef = ffi.new("float[]", coef)
      lib.TCOD_heightmap_add_voronoi(
          _heightmap_cdata(hm),
          nbPoints,
          nbCoef,
          ccoef,
          rnd.random_c if rnd else ffi.NULL,
      )